Pseudosuchians were the dominant group of archosaurs on continental ecosystems during the Triassic. However, studies that report palaeopathologies based on osteohistological evidence in this group are scarce. Here, two cases of palaeopathologies found in appendicular bones of two clades of pseudosuchians are presented: Aetosauria, a distal fragment of the fibula of Aetosauroides scagliai and Erpetosuchidae, the distal half of the tibia of Tarjadia ruthae from the Ischigualasto and Chañares formations, respectively (province of La Rioja, Argentina). The cortex in both specimens is composed of woven-fibred bone in the deepest part and by parallel-fibred bone in the subperiosteum. Towards the outermost portion of the cortex, a thin layer of periosteal bone with an irregular margin is recorded, mainly formed by a fibrolamellar bone vascularized with relatively wide and anastomosed radial canals. These features are compatible with a specific tissue recognized in pathological conditions, the radial fibrolamellar bone (RFB), generated by periosteal reactive bone. Additionally, a thin layer of parallel-fibred/lamellar bone crossed this structure in A. scagliai and surrounding the outermost portion in both specimens. The presence of RFB shows an abnormally accelerated bony overgrowth. However, due to the short thickness of this layer and the subsequent formation of parallel-fibred bone, it indicates a slowdown in its development and a possible recovery of the pathological condition. The configuration of the injury is compatible with periostitis and it constitutes the first record of this type of pathologies in non-crocodylomorph pseudosuchians. As the causes for this benign injury, it is inferred a non-traumatic stress followed by a pyogenic infection.
Abstract Geochemical proxies are frequently utilized in the reconstruction of past ocean temperatures. Due to resource constraints, these reconstructions typically rely on a single sediment core, raising questions about the local and regional representativeness of paleotemperature records. To address this, we analyzed four sediment cores located within a 10-km radius in the northern Okinawa Trough (OT), which share the same climatic forcing and thus should reflect similar climate variations. We compiled published data and generated new paleotemperature estimates based on three widely used geochemical proxies (foraminiferal Mg/Ca, $${\text{U}}_{37}^{{{\text{K}}^{\prime}}}$$ U 37 K ′ , $${\text{TEX}}_{86}$$ TEX 86 ). Analysis of the mean absolute deviations for nearby records based on the same proxy revealed that $${\text{U}}_{37}^{{{\text{K}}^{\prime}}}$$ U 37 K ′ has the highest reproducibility, followed by Mg/Ca and $${\text{TEX}}_{86}$$ TEX 86 . However, inconsistencies in inter-proxy offsets among nearby sites suggest the presence of noise in the proxy records, likely stemming from instrumental errors and sediment heterogeneity. Furthermore, the Mg/Ca and $${\text{U}}_{37}^{{{\text{K}}^{\prime}}}$$ U 37 K ′ paleotemperature records agree within uncertainty when accounting for inter-site variability and calibration uncertainties, challenging previous interpretations of temperature signals from different seasons. All proxies indicate similar glacial-interglacial trends, albeit with varying magnitudes of temperature change. Both Mg/Ca and $${\text{U}}_{37}^{{{\text{K}}^{\prime}}}$$ U 37 K ′ records suggest a glacial cooling of ~ 3 °C, whereas $${\text{TEX}}_{86}$$ TEX 86 sea surface temperature (SST) data indicate a stronger glacial cooling of approximately ~ 6–8 °C. Modern observations indicate a subsurface $${\text{TEX}}_{86}$$ TEX 86 recording depth of 50–100 m, coinciding with the thermocline. However, the $${\text{TEX}}_{86}$$ TEX 86 subsurface temperature (subT) record does not resemble the Mg/Ca records of thermocline-dwelling foraminifera species. Instead, there is a better agreement with benthic foraminiferal Mg/Ca records of Uvigerina spp. (~ 700 m) and the intermediate temperature record derived from radiolarian assemblages (~ 500 m), pointing to a $${\text{TEX}}_{86}$$ TEX 86 recording depth that is deeper than the thermocline. In summary, our findings show that proxy noise can impact inter-proxy comparisons of paleotemperature records, but not the direction of glacial-interglacial shifts. Future research should prioritize constraining the recording depth of paleotemperature proxies and reducing calibration uncertainty for more precise and reliable quantitative paleotemperature reconstruction.
The authors discuss the geoarchaeological data indicating that the Oldowan-age assemblages, which are reported during the last years on the Taman peninsula, in the north-western Caucasus, and in Dagestan, in the north-eastern Caucasus, are found in the marine coast environment near the contact with the sea basin, with evidence for the presence of shallow water (in Muhkai II and other localities in Dagestan) or wave activity (in Kermek and other localities on Taman). The marine environment is not reported in any Early Pleistocene archaeological site in either Europe or south-western Asia, or Africa. Moreover, the geological contexts identified in the Early Pleistocene localities in the northern Caucasus correspond to typical conditions for the formation of eoliths or geofacts. The combined archaeological and geoarchaeological indicators strongly suggest that these North Caucasian assemblages most likely represent collections of naturally broken stones that were selected by researchers among fragments of the same rock that is present naturally in these areas.
Christophe Ronez, Jorge D. Carrillo-Briceño, Patrícia Hadler
et al.
We document the first occurrence of Sigmodontinae (Mammalia, Rodentia, Cricetidae) from the Pliocene of northern South America, from the San Gregorio Formation of northwestern Venezuela. The recovered isolated molars are identified as Oligoryzomys sp. and Zygodontomys sp., two currently widespread sigmodontines in South America. These records constitute the oldest representatives of these genera, potentially new species, and the first Pliocene occurrence for Oryzomyini and the whole subfamily outside Argentina. Hypotheses on the historical biogeography of sigmodontines have been constructed almost exclusively using genetic data and the fossils we report provide a new kind of evidence. The occurrence of Oligoryzomys sp. and Zygodontomys sp. in Venezuela provides novel information for the diversification models suggested for Oligoryzomys, by supporting a potential eastern corridor of open environments from northern to southern South America. The presence of sigmodontines from the locality home of the new reports, Norte Casa Chiguaje, is consistent with the palaeoenvironmental conditions originally proposed for it based on mammals and botanical records, being characterized as mixed open grassland/forest areas surrounding permanent freshwater systems. The new sigmodontine evidence is used to discuss the putative scenarios of the ancient evolution of the subfamily in South America, favouring a model in which open areas (savannahs) to the east of the Andes played crucial role aiding or obstructing Late Miocene–Pliocene sigmodontine dispersion southwards.
Summary: Testate amoebae, a polyphyletic protist group inhabiting a wide variety of extant ecosystems, have evolved as far back as early Neoproterozoic. However, their fossil record is discontinuous and biased toward empty shells. Here, we report an arcellinid testate amoeba species, Cangwuella ampulliformis gen. nov., sp. nov., from a shallow-marine community in the Early Devonian of Guangxi, southwestern China. With the aid of scanning electron microscopy and X-ray micro-tomography, we find that the shell of our testate amoeba contains some acetabuliform structures. Although such configuration does not match exactly with the known internal structures in extant testate amoebae, our fossils highlight the potential of exploring the ecological relationships between fossil testate amoebae and their associated organisms, and increase our knowledge on the diversity of testate amoebae in Early Devonian environments.
The crude oils from the reservoirs of Mela-01 and Mela-04 wells located in the Kohat Basin, Pakistan, were geochemically analyzed to evaluate the origin, depositional conditions, and thermal maturity of the rock units and possible facies from which these oils were sourced. Gas chromatography-mass spectrometry (GC-MS) was performed on the samples to obtain biomarker and non-biomarker parameters. Analyzed non-biomarker parameters, including carbon preference index (CPI), terrigenous to aquatic ratio (TAR), isoprenoids pristane to phytane (Pr/Ph), and biomarker parameters, including steranes and dibenzothiophene/phenanthrene (DBT/P) of aromatic compounds, were utilized in the present study to achieve the objectives. Most of these parameters suggest a mixed source of organic matter (marine/terrestrial) with sub-oxic conditions in the source rocks for the analyzed oil samples in the studied wells from Mela oilfield, Kohat Basin. Furthermore, the CPI and different biomarker parameters such as steranes C<sub>29</sub> S/S + R, ββ/αα + ββ), moretane to hopane (M<sub>29</sub>/C<sub>30</sub>H), pentacyclic terpanes C<sub>27</sub> (Ts/Ts + Tm), H<sub>32</sub> (S/S + R) hopanes, and aromatic methylphenanthrene index (MPI) indicate that the analyzed oils have originated from thermally mature rocks falling in the oil window. As the studied Kohat Basin has multiple source rocks and contributes to the major petroleum production of the country, the present investigations reveal that its okthe Mela oils were generated by the strata of mixed organic matter that were deposited in marine sub-oxic conditions. Furthermore, this study suggests that this stratum would also have been produced in unexplored surrounding areas such as Tirah, Orakzai, and the Bannu Depression.
Abstract Background Dinosaur eggs containing embryos are rare, limiting our understanding of dinosaur development. Recently, a clutch of subspherical dinosaur eggs was discovered while blasting for a construction project in the Upper Cretaceous red beds (Hekou Formation) of the Ganzhou Basin, Jiangxi Province, China. At least two of the eggs contain identifiable hadrosauroid embryos, described here for the first time. Results The eggs, attributable to Spheroolithidae indet., are thin-walled and small (~ 660 mL) compared to those of Lambeosaurinae. The shape of the embryonic squamosal is reminiscent of that seen in the Late Cretaceous hadrosauroids Levnesovia transoxiana, Tanius sinensis, and Nanningosaurus dashiensis, suggestive of possible affinities. Conclusion The small size of the eggs and embryos, similar to those of Hadrosaurinae, indicates that the larger eggs and hatchlings typical of Lambeosaurinae are evolutionarily derived.
A new finding of a coelacanth from the upper Ladinian upper Kalkschieferzone of the Meride Limestone Formation of Monte San Giorgio (UNESCO World Heritage area) is described. It represents the first known coelacanth from the Middle Triassic that undoubtedly bears elongate thin ribs. The incompleteness of the specimen prevents a reliable taxonomic assignment or the erection of a new species, however some characters, mainly scale morphology, are very similar to those of the holotype of Heptanema paradoxum Bellotti, 1857 from the roughly coeval Perledo Formation of Northern Italy. Elongate ribs are not reported in original descriptions of H. paradoxum, however small portion of ribs are visible among the scales of the holotype. Accordingly, the new specimen is tentatively ascribed to Heptanema as Heptanema cf H. paradoxum.
Serita Van der Wal, Mario Schädel, Boris Ekrt
et al.
A collection of exceptionally well-preserved fossil specimens of crustaceans, clearly representatives of Isopoda, is presented here. Excavated from the late Eocene (approximately 40 million years ago) freshwater sediments of the Trupelník hill field site near Kučlín, Czech Republic, these specimens are preserved with many details of the appendages. The morphological characteristics of the fossils were documented using macro-photography with polarised light, as well as stereo imaging. These characteristics, especially including the trunk appendage morphology, were compared to those of related extant groups from different ontogenetic stages. All specimens are conspecific, representing a single species Parvucymoides dvorakorum gen. et sp. nov. Morphometric analysis of body shapes and sizes of the reconstructed fossils and related extant species were performed. These analyses provided insight into the ontogenetic stages of each reconstructed fossil specimen. In combination with the morphological assessment, the results indicate that the fossils represent at least two (possibly three) developmental stages, including immatures. The morphology of the appendages suggests that these fossils were parasites. The fossils are interpreted as either representatives of Cymothoidae or at least closely related to this group.
A rich assemblage of vertebrate fossils, especially fish and mammals, has been recovered from the Plio—Pleistocene Karewa deposits of Kashmir (J & K, India). Microtine rodents and insectivores, including some new taxa and first reports, form the most significant component of the assemblage. The Karewa vertebrate palaeontology is correlated with the magnetic polarity time scale. The Plio—Pleistocene boundary in Karewas is marked by the appearance of microtine rodents. The fossil assemblage is an admixture of high altitude and Iow altitude fauna. The fauna indicates the occurrence of a mosaic of dominant grassland and wooded grassland with some bush cover and wooded areas. A dominant lacustrine with some glacio—fluvial and aeolian environments are indicated for the Karewa sediments.
Aim of the present paper is the description of an Ammonite fauna collected from the Gebze area (Kokaeli Peninsula, Turkey) by late R. Assereto in 1969 and 1971. Preliminary data on these Ammonites were reported by Assereto (1972), who in 1974 proposed the Kokaeli Peninsula, near the town of Gebze, along the Istanbul-Izmid railway-line from km 49.780 to km 51.500 as type locality of the Bithynian, a new Anisian Substage.
The Qaidam Basin is a large transpressional Mesozoic to Cenozoic basin in the Tibet Plateau, West China. Since the Indosinian Movement, it has been in the subsidence stage and more than 3 trillion cubic meters of natural gas accumulated at the same time. The palaeoclimate evolution during the Pliocene Shizigou stage not only controlled sequence stratigraphy development and evolution, but also worked as a key restraining factor for the largest biogas resource in the world. A case study was made in the well Qijia 1, which is the longest cored well in the Qaidam Basin. The palaeoclimate evolution during the Shizigou stage was reconstructed by using geochemistry methods, including the contents of chloride ion, trace elements and TOC, combined with core data, well logging, paleontology data and sequence stratigraphy. The contents of Sr/Ba and Sr/Ca have a positive correlation with chloride ion, which means that the values of Sr/Ba and Sr/Ca are high in an arid environment. But the contents of Rb/Sr and TOC have a negative correlation with chloride ion, which means that the values of Rb/Sr and TOC are low in an arid environment. The palaeoclimate during the Shizigou stage came through an arid-humid-arid evolution and the water body is brackish water. Based on sequence stratigraphy, five sub-palaeoclimate cycles were recognized for the first time. The palaeoclimate evolution and sequence evolution have the same cyclicity, which shows the controlling function of palaeoclimate.
Adam T. Halamski, Jiří Kvaček, Marcela Svobodová
et al.
Late Cretaceous plants from the North Sudetic Basin (Lower Silesia, south-western Poland) are reviewed on the basis of megaflora from 17 localities (270 identifiable specimens), mesoflora from two localities, and microflora from four localities. Major sites are Rakowice Małe and Bolesławiec. Eight megafloral assemblages are distinguished (Assemblage 1, Turonian; Assemblages 2, 3, lower–middle Coniacian; Assemblages 4, 5, upper Coniacian?–lower Santonian?; Assemblages 6–8, lower–middle Santonian); the bulk of the palaeoflora is from Assemblages 4–6 and 8. Megaflora consists of 29 taxa (6 ferns, 4 conifers, and 19 angiosperms). Geinitzia reichenbachii is the most common species. Dryophyllum westerhausianum (Richter, 1904) Halamski and Kvaček comb. nov. is a trifoliolate leaf re-interpreted as a representative of Fagales. Three species of Dewalquea are distinguished: Dewalquea haldemiana, Dewalquea insignis, and Dewalquea aff. gelindenensis. Platanites willigeri Halamski and Kvaček sp. nov. is characterised by trifoliolate leaves, the median leaflet of which is ovate, unlobed, with a serrate margin, and cuneate base. Palaeocommunities inferred from the megafossil record include: a back swamp forest dominated by Geinitzia, with abundant ferns; a Dryophyllum-dominated riparian forest; a forest with Dewalquea and Platanites willigeri possibly located in the marginal part of the alluvial plain; dunes with D. haldemiana and Konijnenburgia; a fern savanna with patches of Pinus woodlands. Palynoassemblage A from the Nowogrodziec Member, studied mostly at Rakowice Małe and Żeliszów, consists of 126 taxa, including 105 terrestrial palynomorphs (54 bryophyte, lycophyte, and pteridophyte spores, 16 gymnosperms, 35 angiosperms). The mega- and mesofossil records are dominated by angiosperms; the palynoassemblages are dominated by ferns. Palaeocommunities represented solely by the microfossil record are halophytic (with Frenelopsis and unconfirmed presence of Nypa) and pioneer vegetation. Palaeocommunities are intermediate in general character between those pre-dating the Cretaceous Terrestrial Revolution and modern, angiosperm- dominated vegetation. In comparison to older plant assemblages from contiguous areas laurophylls are much rarer; this might correspond to a real phenomenon of exclusion of lauroids from Santonian riparian forests. The studied assemblage is more similar to younger palaeofloras than to older ones; this might be interpreted as stabilisation of communities after a period of pronounced change related to the rise to dominance of the angiosperms. In contrast to widespread endemism among vertebrates of the European Archipelago, the plant cover consists mostly of species that are widely distributed.
Trionychid turtles were widespread throughout much of the Western Interior Basin of North America during the Cretaceous, represented by a wide variety of taxa. Despite their widespread abundance east of the Rocky Mountains, they have not previously been reported from Cretaceous deposits along the Pacific Coast of North America. We report here on an isolated trionychid costal from Vancouver Island, British Columbia. The fossil was recovered from the Late Cretaceous (Turonian to Maastrichtian) Nanaimo Group, on Vancouver Island, British Columbia. While the fossil is generically indeterminate, its presence adds an important datapoint in the biogeographic distribution of Trionychidae.
Newly identified material belonging to the holotype specimen of <i>Ianthodon schultzei</i>
substantially increases our knowledge of this poorly known basal
sphenacodont synapsid from the fossil site in Garnett, Kansas (Missourian, Late
Pennsylvanian). The original description, based on a partial dermal skull
roof, is augmented with information on the palate and braincase, together
with data on the mandible and a few postcranial elements. The known skeletal
morphology resembles that of <i>Haptodus garnettensis</i>, another synapsid taxon known from this
locality, but with fewer marginal, distinctly recurved teeth and smaller
teeth on the transverse flange of the pterygoid. Although recognizing that
the holotype and only known specimen represents a juvenile individual,
<i>Ianthodon</i> appears to reflect a more basal sphenacodontian condition than <i>H. garnettensis</i>. A
restricted phylogenetic analysis based on previous work and newly scored
characters for <i>Ianthodon</i>, <i>Cutleria</i> and <i>Pantelosaurus</i> supports this hypothesis. The Garnett locality
appears to preserve an assemblage of synapsids (<i>Haptodus, Ianthasaurus, Ianthodon</i>) that are close to the base
of the large clade that includes Edaphosauridae and Sphenacodontia,
suggesting that an initial diversification of this clade occurred well within the
Carboniferous Period.
The study of palynomorphs and calcareous nannofossils recovered from the volcano-arenitic succession outcropping at Troina and Cerami (Sicily) documents Rupelian assemblages comparable to those published for the Tusa Tuffite. This new evidence, combined with petrographic, geochemical and sedimentological affinities documented in the literature, eventually proves the genetic relationships between these units. Accordingly, the new name Troina-Tusa Formation is proposed to include all these lower Oligocene volcano-sedimentary units and to replace inappropriate names formerly used. The Troina-Tusa Formation conformably lies on a mixed siliciclastic-carbonate turbidite succession, lacking volcanic detritus, reported in the literature with different names (Polizzi Formation, Varicoloured Shales, Troina-Tusa Flysch) and different ages (ranging from Eocene to Early Miocene). Palynomorphs and nannofossils recovered from its uppermost part, indicate an earliest Oligocene age. The denomination Polizzi Formation is recommended for this unit that includes also the Varicoloured Shales (Eocene-basal Oligocene). The appearance of conglomerates and volcano-arenites in the basal portion of the Troina-Tusa Formation, immediately above the top of the Polizzi Formation, marks a sudden reorganization of the Rupelian depositional systems related to the rise and erosion of a volcanic belt. Apparently, no biostratigraphically detectable hiatus is associated to this boundary. Differences in the composition of sandstones, sedimentary features and relationships with the substratum do exist between the ‘internal’ Reitano Flysch, outcropping in the type-area on the northern slope of the Nebrodi Mountains, and the volcano-arenitic successions of Cerami and Troina, reported by some authors as ‘external’ Reitano Flysch. These differences are widely documented in the literature, where the ‘internal’ Reitano Flysch is shown to lack volcanic detritus and to rest unconformably on the deformed Monte Soro Flysch. Since the definition of the Troina-Tusa Formation now includes the external outcrops (Cerami, Troina, Ancipa Lake), the adjectives ‘internal’ and ‘external’ become disused, and the name Reitano Flysch is restricted to the successions lacking volcanic detritus exposed in the type-area of Reitano, Pettineo, Caronia and Capizzi. Palynomorphs and nannofossils recovered from the Pettineo section, suggest a Rupelian age also for the Reitano Flysch.
The assemblage of foraminifera in turbidite beds in Middle Triassic basinal deposits straddling the Anisian/Ladinian boundary interval was studied in 224 thin sections. The fauna consists mainly of shallow-water inhabitants, associated with calcareous hyaline foraminifera (Lagenina) of open marine environment. Due to a well established biostratigraphy in the studied interval, the first and last appearance of some shallow water, benthic foraminifera can be assigned to the Mid Triassic ammonoid stratigraphy. The species Meandrospira dinarica Kochansky-Devidè & Pantic and Arenovidalina chialingchiagensis Ho are limited to the Reitzi ammonoid zone. The species Variostoma alta Kristan and Hoyenella gr. sinensis both do not superate the Curionii zone in age in the studied succession. The biostratigraphic most important event occurs at the base of the Gredleri zone, with the appearance of the family Involutinidae Bütschli, represented by the genera Lamelliconus and Aulotortus. The faunal composition is similar to those of neighbouring paleoprovinces, but generally a lower faunistical diversification compared to foraminiferal assemblages in the Anisian or Carnian is observed.
Thierry Jacques, Robaszynski Francis, Gardin Silvia
et al.
This paper examines four facets of stratigraphic terminology and usage considered faulty and proposes corrective measures. The four perfectible areas are: (1) The system of dual nomenclature requiring discrete terminologies for the superpositional and temporal aspects of rock units. (2) The premise that a GSSP establishes the base of a stage as being coincident with the top of the preceding stage rather than simply defining it as the boundary between stages. (3) The rejection of supplementary (auxiliary) sections that would broaden the knowledge of a GSSP and enlarge the area in which it is easily usable. (4) The current dual system of nomenclature for Precambrian and Phanerozoic strata is accepted, but a third system is proposed for strata formed in the last 3 to 5 Ma. In addition, the paper advocates a broader use of a limited number of conventions but warns against their proliferation; units shortened thereby would be more difficult to recognize. It points out the clear distinction between these conventions - a matter of administration and general compliance - and knowledge - a domain where free expression of opinion is indispensable -.